Lecture 7 Muscle and tendon injury Flashcards
Tendon
- Collagen tissue, mostly type 1, makes up 80% of tissue
- connects muscle to bone
- transfer force from muscles into skeletal system
- excellent tensile properties
Enthesis
- junction between a tendon and a bone
- fibrocartilage
- enthesopathy, increases the connection points
Myotendinous junction (MTJ)
Connection between tendon and muscle
- Susceptible for injury
Tendon: stress-strain curve
- Relationship between stress and deformation of tendons is the same as for ligaments
Adaption to training
- Tendons adapt to training by increasing cross-sectional area
- Tendon loading every 2-3 days
- compared to muscles, it takes longer time to gain tendon strength
Repetitive tendon injuries
tendons are most often affected by repetitive injuries
Acute tendon injuries
Direct traume, rupture
Tendinopathy
- Umbrella term used for tendon problems
- Mechanism
-> Repetitive tensile (or compressive) loading (e.g., sprinting jumping, changing direction) -> repetitive micro traumas
-> inadequate recovery between loadings
Tendon pathology cook-purdah model
- Reactive tendinopathy: Non-inflammatory, structural changes & thickening of stressed tendon area
- Tendon disrepair: Worsening tendon pathology, tendon structure becomes disorganized
- Degenerative tendinopathy: Chronic stage
Intrinsic risk factors
- older age, male sex, menopause, genetics, systemic conditions, medications, biomechanics, previous injury
Extrinsic risk factors
- training loads, spike in loads, periods of reconditioning, biomechanical change
Diagnosis
- History: Symptoms often
progress - First pain after
exercise - Then pain at the start
of an activity - Finally pain both
during and after
activity - Physical Examination; Palpation –tenderness
- Imaging: US, MRI
Management (Article)
- Education of patients
- load monitoring
- pain monitoring
- exercise based progressive rehabilitation program
Exercise based rehabilitation programs for lower limb tendinopathy
Stage 1: isometric exercises; against a fixed load, static contraction without any visible movement
Stage 2: isotonic and heavy slow resistance exercises
Stage 3: Increase in speed and energy storage exercises
Stage 4: Energy storage and release and sport specific exercises
Other treatments
- Shock wave therapy, laser, and ultrasound
- Medications
- Injectable therapies
- Passive treatments
- Experimental treatments
- Surgery
Tendon rupture
- Acute rupture of a normal and healthy tendon is rare
- commonly occur in athletes and recreational exercisers aged 30-50 years
Eccentric for generation
- Mid-tendon area, usually during changing direction
- bone-tendon junction
Achilles tendon, suprespinatus tendon
- partial rupture
- complete rupture
Achilles tendon rupture
- Active mid-aged recreational athletes
- high risk of injury: rapid direction changes, jumps
- usually occur without warning (degenerative changes)
Mechanism- achilles
- Strong contracture of the lower leg musculature, with simultaneous extension
-> eccentric loading of the tendon
Diagnosis-achilles
- Acute, intense pain
- audible ‘SNAP’
- reduced power in plantar flexion
- ‘gap’ in the tendon tissue
- bruise and swelling
- ultrasound/ MRI
Treatment and rehabilitation
- conservative vs. surgical repair (end to end suture)
- cast
- rehabilitation and return to sport
Preventions strategies?- achilles
Appropriate loading, strength and conditioning, neuromuscular training
Muscle
- Function: generate force
- Muscle cells (fibres)
Muscle actions
- Isometric
- Isotonic
- Concentric
- Eccentric (most risky for injury)
Muscle: adaption to training
- raid response to training
- neural and muscular factors
- muscle fibres increase their cross-sectional area (hypertrophy)
Muscle injury types
- Direct trauma: contusion, muscular laceration
- Distension ruptures: muscle strain
- Other: DOM’s, myositis ossificans, muscle cramps
Muscle contusion
- Muscle bruise
- external force
- contact sports, team ball sports
- most common sit is the quadriceps
Muscle strain
- tensile force
- usually close to MTJ
- hamstrings, quadriceps, gastrocnemius
- pop, bump, swelling
- Pain on active contraction and passive stretch, reduced contration strength, decreased ROM and loss of function
Clinical grading of muscle strains
Grade 1(mild): few ‘fiber’ injury, minimal loss of strength and motion
Grade 2(moderate): tissue damage, decreased ability to contract and decreased ROM
Grade 3(severe): complete tear, complete loss of muscle function
Hamstring rupture
- Two injury types
- Type I – Sprinting-related hamstring strain (biceps femoris)
- Type II – Stretching-related hamstring strain (semimembranosus)
Type I Hamstring diagnosis
- History & Physical examination
- Mechanism
- Palpation
- Imaging
- MRI
Type II hamstring diagnosis
- History & Physical examination
- Mechanism
- Palpation
- Imaging
- MRI
Muscle injury: healing
- Destructive Phase (Hemostasis & Inflammation)
- Repair Phase (Proliferation)
- Maturation Phase (Remodeling)
Rehabilitation
- Mobilization
- progressive strengthening
- functional exercises (e.g., running program)
- other body regions
Prevention of hamstring strains
stretching- no evidence for sport
